Alix Germany / ntp-client

NTP networking client stuff

Dependents:   Coursework_Version_6 Coursework_Version_8 ELEC351-Coursework

NTPClient.cpp@1:099750f42b02, 2018-12-07 (annotated)

Committer:
Alix955
Date:
Fri Dec 07 13:07:56 2018 +0000
Revision:
1:099750f42b02
Parent:
0:3c1170035e2b 
ntp client stuff;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Alix955 0:3c1170035e2b 1 #include "ntp-client/NTPClient.h"
Alix955 0:3c1170035e2b 2 #include "mbed.h"
Alix955 0:3c1170035e2b 3
Alix955 0:3c1170035e2b 4 NTPClient::NTPClient(NetworkInterface *iface)
Alix955 0:3c1170035e2b 5 : iface(iface), nist_server_address((char *)NTP_DEFULT_NIST_SERVER_ADDRESS), nist_server_port(NTP_DEFULT_NIST_SERVER_PORT) {
Alix955 0:3c1170035e2b 6 }
Alix955 0:3c1170035e2b 7
Alix955 0:3c1170035e2b 8 void NTPClient::set_server(char* server, int port){
Alix955 0:3c1170035e2b 9 nist_server_address = server;
Alix955 0:3c1170035e2b 10 nist_server_port = port;
Alix955 0:3c1170035e2b 11 }
Alix955 0:3c1170035e2b 12
Alix955 0:3c1170035e2b 13 time_t NTPClient::get_timestamp(int timeout) {
Alix955 0:3c1170035e2b 14 const time_t TIME1970 = (time_t)2208988800UL;
Alix955 0:3c1170035e2b 15 int ntp_send_values[12] = {0};
Alix955 0:3c1170035e2b 16 int ntp_recv_values[12] = {0};
Alix955 0:3c1170035e2b 17
Alix955 0:3c1170035e2b 18 SocketAddress nist;
Alix955 0:3c1170035e2b 19 int ret_gethostbyname = iface->gethostbyname(nist_server_address, &nist);
Alix955 0:3c1170035e2b 20
Alix955 0:3c1170035e2b 21 if (ret_gethostbyname < 0) {
Alix955 0:3c1170035e2b 22 // Network error on DNS lookup
Alix955 1:099750f42b02 23 printf("Error on DNS lookup : %d\n" , ret_gethostbyname);
Alix955 0:3c1170035e2b 24 return ret_gethostbyname;
Alix955 0:3c1170035e2b 25 }
Alix955 0:3c1170035e2b 26
Alix955 0:3c1170035e2b 27 nist.set_port(nist_server_port);
Alix955 0:3c1170035e2b 28
Alix955 0:3c1170035e2b 29 memset(ntp_send_values, 0x00, sizeof(ntp_send_values));
Alix955 0:3c1170035e2b 30 ntp_send_values[0] = '\x1b';
Alix955 0:3c1170035e2b 31
Alix955 0:3c1170035e2b 32 memset(ntp_recv_values, 0x00, sizeof(ntp_recv_values));
Alix955 0:3c1170035e2b 33
Alix955 0:3c1170035e2b 34 UDPSocket sock;
Alix955 0:3c1170035e2b 35 sock.open(iface);
Alix955 0:3c1170035e2b 36 sock.set_timeout(timeout);
Alix955 0:3c1170035e2b 37
Alix955 0:3c1170035e2b 38 sock.sendto(nist, (void*)ntp_send_values, sizeof(ntp_send_values));
Alix955 0:3c1170035e2b 39
Alix955 0:3c1170035e2b 40 SocketAddress source;
Alix955 0:3c1170035e2b 41 const int n = sock.recvfrom(&source, (void*)ntp_recv_values, sizeof(ntp_recv_values));
Alix955 0:3c1170035e2b 42
Alix955 0:3c1170035e2b 43 if (n > 10) {
Alix955 0:3c1170035e2b 44 return ntohl(ntp_recv_values[10]) - TIME1970;
Alix955 0:3c1170035e2b 45 } else {
Alix955 0:3c1170035e2b 46 if (n < 0) {
Alix955 0:3c1170035e2b 47 // Network error
Alix955 1:099750f42b02 48 printf("Network error: %d\n", n);
Alix955 0:3c1170035e2b 49 return n;
Alix955 0:3c1170035e2b 50 } else {
Alix955 0:3c1170035e2b 51 // No or partial data returned
Alix955 1:099750f42b02 52 printf("No or partial data returned: -1");
Alix955 0:3c1170035e2b 53 return -1;
Alix955 0:3c1170035e2b 54 }
Alix955 0:3c1170035e2b 55 }
Alix955 0:3c1170035e2b 56 }
Alix955 0:3c1170035e2b 57
Alix955 0:3c1170035e2b 58 uint32_t NTPClient::ntohl(uint32_t x) {
Alix955 0:3c1170035e2b 59 uint32_t ret = (x & 0xff) << 24;
Alix955 0:3c1170035e2b 60 ret |= (x & 0xff00) << 8;
Alix955 0:3c1170035e2b 61 ret |= (x & 0xff0000UL) >> 8;
Alix955 0:3c1170035e2b 62 ret |= (x & 0xff000000UL) >> 24;
Alix955 0:3c1170035e2b 63 return ret;
Alix955 0:3c1170035e2b 64 }